What is the complexity of searching for an element by value in a list (Python list)?

Searching for an element by value in a Python list (list) has a time complexity of O(n), where n is the number of elements in the list. This is because a list is an ordered collection, and to find an element using the in method or list.index(), you need to iterate through the elements from the beginning until a match is found.

Example:

my_list = [10, 20, 30, 40, 50]
value = 30
if value in my_list:
    print("Found")

Here, in the worst case, all elements of the list will be checked.